Surgical cutting instrument

ABSTRACT

The invention relates to a remotely operable surgical cutting instrument, useful, for instance, in microsurgical procedures, having a two portion main body with one portion oriented at an angle with respect to the other, and a blade having an arcuate cutting edge mounted at one end of the body.

RELATED APPLICATIONS

This application is a continuation-in-part application of U.S. Ser. No.08/162,807, filed Dec. 3, 1993, now abandoned, which in turn is acontinuation application of U.S. Ser. No. 07/871,265, filed Apr. 16,1992, now abandoned.

FIELD OF THE INVENTION

The present invention relates to surgical cutting instruments,especially small scale, remotely operable surgical knives or scissors,useful for performing microsurgical procedures.

BACKGROUND OF THE INVENTION

A common procedure in ophthalmology to remove cataracts is to usephacoemulcification and suction to remove the affected lens from theeye. This procedure is shown and described, for instance, in Cupler,U.S. Pat. No. 4,002,169, in which access to the lens is achieved throughthe sclera or limbus, then through the opening in the iris, and finallythrough the anterior capsular membrane. Although, as shown in Cupler, itmay be possible to gain access to the lens and remove it by piercing theanterior capsular membrane, it is more common to remove a circular pieceof the membrane by a "capsulotomy" procedure, for example by tearing outa portion of the membrane with a needle and forceps. Alternatively, itis known to free the desired membrane portion with a surgical knife. Inthis type of procedure, it is essential to maintain the cutting edge ofthe knife so that it is oriented in the proper direction during theentire circular cut. This may be difficult if the cutting instrument isintroduced through the single incision in the sclera that is used forthe other steps in the cataract removal.

One example of a surgical knife appropriate for a capsulotomy isdisclosed in Pazandak, U.S. Pat. No. 4,708,138, in which a knife bladeis attached to an extension handle at a swivel point, the cuttingportion of the blade being off center from the swivel point. The knifeis directed by sideways motion of the end of the handle removed from theblade attachment point, and the shape and method of attachment of thecutting blade to the handle cause the blade to orient itself with thecutting edge forward, in the direction of movement of the blade, as longas movement of the blade is continuous.

SUMMARY OF THE INVENTION

The invention features a surgical knife useful in microsurgicalprocedures that includes a two portion main body with one portionoriented at an angle with respect to the other portion, and a bladehaving an arcuate cutting edge, the blade being mounted at one end ofthe body and the orientation of the blade with respect to the body beingalterable during cutting.

As used herein, "arcuate" refers to a curved shape as in a semi-circularor circular shape. Thus, in preferred embodiments, the arcuate blade isa cutting edge of semi-circular or circular shape. "Semi-circular"refers to a cutting edge that does not form a complete circle, i.e., isless than 360 degrees, preferably less than 240 degrees, most preferablyis about 180 degrees.

The surgical knife is especially useful in tissue cutting procedures inwhich a desired cutting path is chosen by the surgeon. For example, thecutting path may be of a circular or semi-circular shape, as incapsulotomy procedures where a circular piece of ocular tissue is cutand removed, or the cutting path may be straight or angled, e.g., as inarthroscopic or laparoscopic applications. The blade is thus applied tothe tissue along a desired cutting path, and is useful for implementingvarious types of cuts, e.g., for cutting through the tissue, forintermittent cutting, or for scoring of the tissue, depending upon theamount of pressure applied to the tissue through the cutting edge. Theblade also may be configured so as to more easily accomplish aparticular type of tissue cut; for example, for scoring or intermittentcutting. As used herein, "scoring" refers to cutting into a tissue layerwithout cutting through the layer. Alternatively, the blade may beconfigured so as to allow for intermittent cutting through the tissue."Intermittent" cutting refers to implementing discrete cuts through thelayer of tissue to be cut, while leaving uncut tissue in between thediscrete cuts.

In other preferred embodiments, the cutting edge is of a sharpnesssufficient to cut into a tissue layer without cutting through the tissuelayer. As used herein, "sufficient sharpness" refers to a degree ofsharpness that allows for easy and clean piercing of the tissue, withouttearing, upon application of an amount of pressure of the cutting edgeagainst the tissue that is comfortable to the user of the knife. Ofcourse, the amount of pressure that is needed to accomplish a given typeof cut is determined by the skilled user, as described further below.

In yet other preferred embodiments, the cutting edge is eithercontinuous or serrated. As used herein, "serrated" refers to theconventional meaning of this term, e.g., the edge is notched or toothed,the notches or teeth being pointed, flat, or curved at their outer edgeso as to deliver intermittent discrete cuts of a desired length.

In yet other preferred embodiments, the surgical knife further comprisesa linear rotatable element, i.e., a turning unit, disposed within themain instrument body. The blade is mounted on the turning unit at oneend of the main instrument body and is disposed at an angle to theprimary instrument body axis. The orientation of the cutting edge of theblade with respect to the main body is determined by movement of theturning unit at the end distal to the blade mounting end.

In another aspect, the surgical knife includes a turning unit comprisingeither a flexible element having greater flexibility than the main bodyor a band, the flexible element or band being aligned along the primaryaxis within the main body and cooperating with a blade mount at one endand a knob at the other end of the main body so as to allow alterationof the orientation of the blade with respect to the main body.

Preferably, the knife includes a blade mount and a knob; and the band iswrapped around the blade mount at one end and the knob at the other endof the main body.

The invention also features a remotely operable surgical knife thatincludes a tubular main body having a primary axis and a turning unitdisposed within the main instrument body. A blade is mounted on theturning unit at one end of the main instrument body and is disposed atan angle to the primary instrument body axis. The orientation of thecutting edge of the blade with respect to the main body is determined bymovement of the turning unit at the end distal to the blade mountingend.

Preferred embodiments of the surgical knife include a tubular main bodywhich is an elongated first portion, open at one end, and a shortersecond portion, open at one end and extending from the first portiondistal to the open end of the first portion to form an angle greaterthan 45° to the first portion. The turning unit of the knife includes aturning mechanism in the main body at the juncture of the first andsecond portions; a linear rotatable element disposed through the mainbody, e.g., a movable rod or wire or other connecting element throughthe first portion of the main body, which has one end attached to theturning mechanism; and a blade mounting portion in the second portion ofthe main body and attached to the turning mechanism. The blade ismounted on the blade mounting portion of the turning unit, and movementof the other end of the moveable element causes rotation of the bladeabout an axis generally aligned with the second portion of the mainbody. The blade may be discarded and replaced with a fresh blade foreach use. Alternatively, the entire surgical knife may be discardedafter use.

Preferably, the angle between the first and second portions of the mainbody of the knife is between 80° and 110°, and the knife blade is of acircular configuration. The turning mechanism of the turning unit ispreferably a micro gear unit, for example, transversely oriented bevelgears or a rack and pinion unit. Alternatively, the turning mechanismincludes a flexible element, such as a silicone rubber, a polyurethaneelastomer, or a coiled spring, that has greater flexibility than themovable element portion of the unit. Or the entire turning unit couldcomprise a rotatable element disposed through the body of the knife.

In another embodiment, the body of the instrument and micro gear turningmechanism have similar configurations to those of the surgical knifedescribed above, but the knife blade is replaced by micro dimensionscissors, one handle of which is attached directly to the end of theturning unit. Orientation of the scissors is maintained along thedesired cutting path by rotation of the micro gear turning mechanism,and the scissors are operated to make the desired cut by movement of anadditional wire extending from the scissors through the main body of theinstrument. Preferably, the turning unit and the scissors control wireare operated by manual control elements in the shape of scissorshandles, and portions of the turning unit and the main instrument bodyare flexible.

Because of the small size of the cutting instrument and because movementof the cutting portion is precisely directed from a remote position, aremotely operable surgical cutting instrument according to the inventionis easy to use in small incision surgery, where quick entry to and exitfrom the site of the operation is required. The cutting portion of theinstrument can be directed along the cutting pattern desired at alltimes during the surgical procedure, whether cutting is made in acontinuous process or discontinuously. In the circular or semicircularconfiguration the knife blade of the surgical knife is readilyreversible. The particular advantages of a circular blade are that theknife edge covers a larger surface of the eye and therefore can givebetter depth control. The cutting instrument is simple and rugged indesign. Therefore, numerous embodiments can be inexpensivelymanufactured from readily available materials and then discarded withoutincurring any great expense.

The invention also encompasses methods of performing microsurgery usingembodiments of the surgical knife described herein.

Thus, in one method, the arcuate cutting edge is applied to a tissuelayer and moved along a chosen cutting path. The pressure applied to thetissue layer is sufficient to cut through the layer of tissue withouttearing or otherwise damaging the tissue.

In another method, known as "scoring", a surgical knife in which theblade comprises an arcuate or pointed cutting edge, as described herein,is used. The scoring method includes applying the arcuate cutting edgeto a tissue layer with pressure of the cutting edge against the tissuelayer sufficient to cut into the tissue layer in a continuous manner,but insufficient to cut through the tissue layer. Once the tissue isscored, the tissue layer is then peeled or pulled off. In this scoringmethod, a conventional sharp cutting edge may be used provided thepressure applied to the cutting edge against the tissue layer is lessthan the pressure that is applied to the same tissue using the samecutting edge sharpness when making a cut completely through the tissuelayer. The amount of pressure necessary to perform the procedure will,of course, be judged by one of skill in the art during the surgicalprocedure, e.g., the surgeon performing the procedure.

Alternatively, the scoring method may employ a cutting edge that is lesssharp than a conventional edge such that the pressure applied to thecutting edge against the tissue layer need not be less than the normalamount of pressure using a sharp edge, and may in fact be increased.Again, the amount of pressure necessary to achieve scoring of the tissuelayer will be determined by the skilled surgeon during the procedure.The pressure will vary according to the type of tissue to be cut, thethickness of the tissue layer, and the relative sharpness of the cuttingedge.

In preferred embodiments of this method of the invention, cutting may bein a continuous manner or may be intermittent.

Another method of the invention employs a surgical knife having aserrated cutting edge. This method, known as "intermittent" cutting,involves applying the serrated cutting edge to the tissue layer in acontinuous manner using an amount of pressure sufficient to achieveintermittent cuts through the tissue. When a serrated cutting edge isused, pressure will be applied continuously, with the serrations in thecutting edge accomplishing the desired dis-continuous cutting pattern.Thereafter, the cut tissue is peeled or pulled off.

An alternative method of intermittent cutting is achieved using anon-serrated blade, i.e., a blade of continuous sharpness along itsarcuate cutting edge. According to this method, the blade is applied tothe tissue layer in a dis-continuous manner. That is, the cutting edgecuts into the tissue upon application of pressure on the blade againstthe tissue layer, pressure is then released for a chosen distance alongthe cutting path, and then alternately reapplied and released. The cuttissue is then peeled or pulled off.

The invention will be more fully understood with reference to thedetailed description, the accompanying drawings, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings are first briefly described.

FIG. 1 is a side perspective view of a surgical knife according to theinvention;

FIG. 2 is a side perspective view of another embodiment of a surgicalknife according to the invention;

FIG. 3 is a side perspective view of another embodiment of a surgicalknife according to the invention;

FIG. 4 is an axial sectional view of a human eye, showing the inventionin use;

FIG. 5 is a transverse sectional view of the eye, showing the path takenby a capsulotomy knife according to the invention during use; and

FIG. 6 is a side perspective view of an embodiment having micro surgicalscissors according to the invention.

FIG. 7 is a side perspective view of an embodiment of the arcuatecutting edge shown in FIG. 1, in which the cutting edge is serrated.

FIG. 8 is a side perspective view of another embodiment of the arcuatecutting edge shown in FIG. 1, in which the cutting edge is alsoserrated.

FIG. 9 is a side perspective view of another embodiment of the turningmechanism of a surgical knife of the invention.

FIG. 10 is a side perspective view of yet another embodiment of theturning mechanism of a surgical knife of the invention.

DESCRIPTION OF PREFERRED EMBODIMENTS

A surgical knife for micro surgery must be sized at its cutting end soas to permit insertion into the micro scale surgical field of the targettissue and yet be large enough at its opposite end to be heldcomfortably in the hand of the operating surgeon. Preferably, the knifeis configured so that it may be introduced through the single incisioninto the portion of the body containing the target tissue. For example,a surgical knife for capsulotomy must be sized at its cutting end so asto permit insertion into the relatively small field of the eye. Theknife will be configured so as to be introduced via a single incisioninto the sclera that is used for other steps in cataract removal.

The description provided below of the surgical knife of the inventionand methods of use therefore is made with respect to a capsulotomy knifeand procedure. It will be understood that the surgical knife is notintended solely for capsulotomy procedures, but may be used in othertypes of surgical procedures that require entry into the surgical sitewith a minimum of intrusion, cutting of a tissue at a target site, andmanipulation of the cutting blade at the cutting site via a mechanismwhich places the surgeon's hand at a distance from the target site. Itwill be readily apparent to one of skill in the art that the knife maybe used in procedures other than capsulotomy and how to perform suchprocedures using a surgical knife of the invention.

Referring first to FIG. 1, a capsulotomy knife 10 has a 15 cm longtubular main body 12 of either plastic or stainless steel, which is openat each end and includes an elongated first portion 14 and a relativelyshort second portion 16. The elongated portion of the knife includes ahandle 15 of approximately 7 mm in diameter and steps down to a diameterof less than 1 mm at the junction with the second portion. The secondportion of the knife extends at a substantial angle to the firstportion; in preferred embodiments of the invention, this angle is80°-110° (preferably 90°).

A turning unit 20 extends through the main body of the knife, having ablade 22 mounted thereon at the open end of the second portion of thebody and a control knob 24 at the open end of the first portion. Knifeblade 22 is attached by any convenient means, and blade mounting portion28 is journalled for rotation, as shown, or in any other convenientmanner to suit the particular implementation. The turning unit itselfcomprises three sections: first, a movable polytetrafluoroethylene(e.g., Teflon®) or stainless steel rod 26 through the first portion 14of the main body, which attaches to the control knob; second, a blademounting portion 28 through the second portion 16 of the main knifebody, to which knife blade 22 is attached; and, third, a micro gearturning mechanism 30 at the juncture of the first and second portions,which connects the movable wire with the blade mounting portion of theunit. As shown in FIG. 1, knife blade 22 is circular and is suspendedfrom blade mount 32. However, numerous other blade configurations, suchas semi-circular or triangular as shown in FIGS. 2 and 3, are suitabledepending on the application. Micro gear mechanism 30 has two edgeengaging bevel gears 34, 36 oriented at right angles and supported bybushings 31, 33. Rotation of control knob 24 by a surgeon, andconsequent rotation of rod 26 and bevel gear 34, is translated intorotation of bevel gear 36 and knife blade mount pin 32 and, thus,positive controlled rotation of the knife blade itself a full 360°. Atypical micro gear, which can be stainless steel or plastic, is about0.5 mm in diameter, the dimensions of a gear in a small analog watch,and can be machined to have bevelled edges at any desired angle.

In an alternate configuration 40, shown in FIG. 2, micro gear mechanism42 comprises a rack gear 44 mounted on the end of movable rod 45 andengaging the teeth of a pinion gear 46, to which knife blade 48 isattached. Slide control knob 50 is connected to rod 45 through a slideopening 52 in main knife body portion 14. As the slide control knob ismoved by a surgeon within slide opening 52, passage of the rack gear 44past the side of pinion gear 46 causes rotation of the gear and, thus,rotation of the knife blade 48. In this FIG. 2 embodiment, part of themain knife body portion 14 extends past the micro gear mechanism toaccommodate the movement of rack gear 44.

In an alternative embodiment 100 of the rack gear mechanism, shown inFIG. 9, slide control knob 50 operates movement of rack gear 44 past theside of pinion gear 46 via turning of knob 50. In order to minimize anysideways motion of knob 50 during use, knob 50 may be attached at itsdistal end to main body 12 via adaptor 13. Knob 50 is journalled whereit contacts movable rod 45, which is also journalled. Knob 50 thuscooperates with rod 45 such that turning of knob 50 in either directionresults in movement of rod 45. Movement of rod 45 translates intoturning of blade 48 via cooperation between the journalled portions ofrack gear 44 and pinion gear 46, as described above. Slide control knob50 may turn up to 360 degrees or more, in either direction, until blade48 is correspondingly turned to the desired degree. Optimally, controlknob 50 is turned until blade 48 is correspondingly turned toapproximately a 60 degree angle in either direction. In the variousembodiments of the invention, the entire instrument is on the order of90-160 mm in length, optimally approximately 120-130 mm in length, theshaft diameter at the leading (i.e., blade-attachment) end of the shaftis on the order of 1-4 mm and optimally 2-3 mm in diameter, and theblade is on the order of 1-3 mm in width and 0.5-2 mm in height,optimally 1.5 mm width and 1 mm height. The instrument is generally of asize which allows for holding of the handle in the palm of the hand. Forthose embodiments including a knob in the handle portion of theinstrument, the knob may be operated with the thumb or index finger ofthe same hand that holds the instrument.

In a fourth embodiment 110 of the capsulotomy knife, shown in FIG. 10,the turning mechanism comprises a turning knob 50 and a band 120extending around or attached to the turning knob 50 at one end andextending through the handle 12 of the instrument and wound around theblade pinion gear 46' at the other end. In this embodiment, pinion gear46' is journalled horizontally for rotation such that band 120 may catchin a crevice of the journalled portion of gear 46'. Knob 50 is alsohorizontally journalled such that band 120 wraps around knob 50 and maycatch in a crevice of the journalled portion of knob 50. Turning of theblade 48 is accomplished by turning of knob 50; tension in band 120 issufficient to create friction between the band and the journalled gear46', thus causing mounting portion 28 and attached blade 48 to turn in adesired direction and to a desired degree. The band may be made of anymaterial in which tension may be induced sufficient to cause frictionalmovement of the journalled blade mounting portion 28. For example, theband may be made of an elastomeric material such as a rubber, or anon-elastomeric material such as a flexible plastic or metal.

In a fifth embodiment 60 of the capsulotomy knife, shown in FIG. 3, theturning mechanism 62 of the turning unit is simply an element that ismore flexible than the main portion of the unit so that turning unit 20can accommodate to the shape of the main knife body 12 without kinking.A suitable element to provide this function is a coiled wire springwhich is attached at respective ends of moveable rod 26 and the blademounting portion 28. A flexible material such as a length of siliconerubber, Teflon®, or polyurethane elastomer would also serve the samepurpose. The flexible nature of the turning mechanism of embodiment 60allows rotation of knob 24 to result directly in rotation of thesurgical knife blade 64.

The cutting edge of the blade portion of a surgical knife according tothe invention is, as described herein, of an arcuate or triangular(diamond) shape, with an arcuate shape being a semi-circular or circularshape. A cutting edge useful in the invention may be an extremely sharp,fine edge or may be slightly less sharp or relatively dull, as theprocedure requires. As described above, less sharp or relatively dulledges are especially useful in scoring types of cutting methods. Inaddition, a cutting edge useful in the invention will typically be acontinuous edge with no serrations. Alternatively, the cutting edge maybe serrated, as shown in FIGS. 7 and 8. FIG. 7 shows a serrated cuttingedge 130 in which the teeth 132 are triangular or diamond shaped andinterrupted by recessed areas 132 that do not make cutting contact withthe tissue. FIG. 8 shows a serrated cutting edge 140 in which the teeth142 present an arcuate cutting edge and are interrupted by recessedportions 144 that do not make cutting contact with the tissue. Thus, theserrated cutting edges allow for implementation of discontinuous orintermittent cuts along the target cutting line.

The operation and the advantages of the present invention will now bereadily understood in view of the above description. FIGS. 4 and 5demonstrate the manner in which a capsulotomy knife is used in thecapsulotomy procedure on a human eye 70. An incision 72 is made throughthe sclera and conjunctiva, the cornea is lifted, and the knife 10 isinserted into the eye. The second portion 16 of knife 10 is then passedthrough the dilated iris 74 and turned so that it is oriented axially ofthe eye and is positioned above and at a right angle to the generalplane of the anterior capsular membrane 76, which overlies the lens 78,the portion of the eye eventually to be removed.

At this point in the procedure, the knife is lowered and the blade 22 ismoved along a circular path 77 defining the section of the anteriorcapsular membrane to be removed. As shown in FIG. 5, the orientation ofthe knife blade along the circular path is maintained by rotation of theturning knob 24. This movement serves to rotate blade 22 with respect tothe main body of the knife, as described above. The aspect of the bladeand its maintenance on the selected path can be facilitated throughmicroscopic observation, as is customary in such surgical procedures.

Additional operations and advantages of the present invention are foundin the uses of the various cutting edges disclosed herein. Thecontinuous arcuate cutting edge (as pictured in FIG. 1) may be used tomake a continuous cut through a tissue layer, a dis-continuous (i.e.,intermittent) cut through the layer, or a scored type of cut into butnot completely through the tissue layer. These three types of cuttingare accomplished using a single blade configuration by varying thepressure applied to the instrument during cutting and by varying thelength of tissue cut along the cutting path. For example, a continuouscut through the tissue layer is achieved by applying enough continuouspressure through the blade cutting edge against the tissue layer toallow the cutting edge to slice through the tissue layer. This amount ofpressure is then maintained as the blade is guided along the chosencutting path. As explained above, one of skill in the art, havingpracticed the selected type of surgery many times, and being familiarwith the relative strength of the target tissue and blade sharpness,will easily determine what amount of pressure is needed to accomplishthe task.

Alternatively, where dis-continuous cutting of a tissue layer is desiredusing the continuous cutting edge, the pressure manually applied to theinstrument by the hand of the surgeon, is varied for a time sufficientto implement discrete cuts through the tissue layer along the chosencutting path. Thus, when pressure is applied to the instrument, thecutting edge cuts through the tissue layer for a first given distancealong the cutting path. This is followed by releasing the appliedpressure enough to disengage the sharp cutting edge from the tissuesurface for a second given distance. Thereafter, pressure is reappliedand released as many times as is necessary to complete the cutting path.The uncut portions of tissue between the cut portions serve to helpmaintain an intact tissue layer and thus to prevent tearing prior toremoval of the cut layer of tissue. At the same time, implementation ofdiscrete intermittent cuts in this way allows for easy removal of thecut tissue by simply lifting the cut tissue layer and pulling the cuttissue away from its actual position. The uncut intermittent portions oftissue will neatly tear between the cut portions to complete the cutpath.

Yet another cutting method utilizing the continuous cutting edge isreferred to hereinabove as scoring of tissue. A sharp continuous edgemay be used to score a tissue layer, i.e., to cut into the layer along acutting path without cutting through it, by applying an amount ofpressure that is insufficient to result in a cut completely through thetissue layer. Again, this amount of pressure will be carefully chosen bythe skilled user of the instrument based on the sharpness of the blade,thickness of the tissue, and the relative resistance of the tissue layerto cutting. A tissue layer which has been scored along a chosen cuttingpath may be easily removed by pulling on the tissue to induce a tear inthe tissue along the scored path. The scored tissue will tear clearlyalong that path. Of course, the scoring method may be performed using arelatively less sharp or a dull cutting edge, by applying relativelymore pressure to the instrument, as needed.

The above-identified cutting methods also may be accomplished using ablade other than a blade having a continuous cutting edge. For example,where intermittent cutting is desired, the user may prefer to utilize aserrated cutting edge. Where a serrated edge is used, e.g., see FIGS. 7and 8, varying the application and release of pressure to the instrumentis unnecessary to accomplish discontinuous cutting. Instead, thediscontinuous configuration of the blade cutting edge itselfaccomplishes the task. That is, the portions of the cutting edge thatjut outward, i.e., the teeth, will meet the tissue layer first and, uponapplication and maintenance of pressure to the instrument, will cutthrough the tissue layer. The alternating recessed portions either willnot contact the tissue or will contact it in such a manner so as toleave intermittent portions of the tissue uncut or scored. The serratedblade is guided by the surgeon along the cutting path of the tissue.During movement of the blade, a relatively invariant amount of pressureis applied to the instrument. Again, the choice of pressure isdetermined by the skilled user by taking into account a number offactors, as explained above.

It can be seen, then, that the capsulotomy knife of the invention can becontrolled very accurately and easily so that its sharp edge is alwaysdirected along the desired cutting path. The simplicity and ruggednature of the knife mean that it can have a long life of useful service.The knife can be made with a blade mounting unit capable of handlinginterchangeable blades so as to prolong its useful life. Alternatively,a knife made of inexpensive materials can be considered disposable.

A knife according to the invention would be useful not only in ocularsurgery but also in any kind of arthroscopic or laparoscopic procedure,e.g., in the knee, in the belly for cutting around the gall bladder, orin the brain. For this type of use, the main body of the knife and themoveable rod portion of the turning unit could be made of a flexibleplastic. In addition, other surgical cutting instruments for use whereprecise but remote control is needed, could be fashioned in the sameway.

For example, as shown in FIG. 6, surgical scissors 80, with a rotatabletravel path of more than 270° in either direction, have a tubular mainbody 12 through which extends turning unit 20 with a micro gearmechanism 30 similar to that for a capsulotomy knife turning mechanism.Micro scissors 82, which are spring loaded with a sheathed coiled spring83 so as to remain in an open position until urged closed, are stifflymounted by one scissors handle 84 to the short end of turning unit 20. Aflexible wire 88, which is connected by a small ball joint pivot tounattached scissors handle 86, runs from the scissors handle backthrough the tubular instrument body 12, adjacent to the turning unit.Knurled barrel handle 13 closes off the open end of the long section ofthe instrument body, and supported at the end of the handle are opposedscissors loop handles 90 and 92. Loop 90 is stiffly connected to theturning unit and extends above a plane through its axis. Loop 92 isconnected by pivot 94 to barrel handle 13 and extends below the turningunit plane. Flexible wire 88, extending from the lower scissors handle86, is attached to lower loop 92 by a hinge 96.

To operate the scissors, the surgeon inserts the thumb of the dominanthand into loop 90 and the middle finger into loop 92. A twisting motionof the hand will cause the turning mechanism to rotate, as describedbefore, and will result in positive controlled rotation of the microscissors. In this manner, the scissors can be kept oriented along adesired cutting path. To provide the scissors cutting action, thesurgeon applies pressure from the middle finger on loop 92 and squeezesthe loop upwards, towards loop 90. This movement flexes hinge 94 andconsequently applies a pulling action to wire 88. Action of the wire onscissors handle 86 then brings the cutting edges of the scissors intojuxtaposition. As soon as the pressure on loop 92 is released, action ofspring 83 forces scissors handles 84 and 86 apart and restores thescissors to their open configuration.

Other embodiments of the invention will be apparent to those skilled inthe art from a consideration of this specification or practice of theinvention disclosed herein. It is intended that the specification andthe examples be considered as exemplary only, with the true scope andspirit of the invention being indicated by the following claims.

What is claimed is:
 1. A surgical knife comprising:a tubular main bodyhaving a primary axis, a first housing portion aligned along the primaryaxis, and a second housing portion disposed adjacent to the firsthousing portion; a blade mount attached to the second housing portionand journaled for rotation about a secondary axis disposed at an anglewith respect to the primary axis; and a blade having a cutting edge, theblade mounted to the blade mount to extend from the second housingportion of the tubular body along the secondary axis; a turning unitdisposed within the second housing portion in cooperation with the blademount to rotate the blade mount; and a movement control element disposedto extend from the first housing portion of the main body andoperatively connected to the turning unit to cause movement of theturning unit, wherein movement of the control element causes rotation ofthe blade about the secondary axis.
 2. The surgical knife of claim 1,said cutting edge comprising a semi-circular shape.
 3. The surgicalknife of claim 1, said cutting edge being of a sharpness sufficient tocut into a tissue layer without cutting through said tissue layer. 4.The surgical knife of claim 1, said cutting edge being continuous. 5.The surgical knife of claim 1, said cutting edge being serrated.
 6. Amethod of performing micro surgery on a tissue of the body, said methodcomprising the steps ofproviding the surgical knife of claim 5; andapplying said serrated cutting edge to the tissue layer in a continuousmanner upon movement of the cutting edge along a cutting path using anamount of pressure sufficient to achieve intermittent cuts through thetissue layer.
 7. A method of performing micro surgery on a tissue of thebody, said method comprising the steps ofproviding the surgical knife ofclaim 1; and applying the cutting edge of said knife to a tissue layerwith pressure sufficient to cut through said tissue layer in acontinuous manner upon movement of said edge along a cutting path.
 8. Amethod of performing micro surgery on a tissue of the body, said methodcomprising the steps of(a) providing the surgical knife of claim 1; (b)applying said cutting edge to a tissue layer sufficient to cut adiscrete length of said tissue layer along a cutting path; and (c)releasing pressure on said cutting edge for a distance along saidcutting path sufficient to leave a discrete length of said tissue layeralong said cutting path uncut.
 9. A method of performing micro surgeryon a tissue of the body, said method comprising the steps ofprovidingthe surgical knife of claim 1 or 3; and applying the cutting edge ofsaid knife to a tissue layer with pressure sufficient to cut into saidtissue layer upon movement of said edge along a cutting path, butinsufficient to cut through said tissue layer.
 10. The method of claim8, further comprising repeating steps (b) and (c).
 11. The method ofclaim 7, 9, or 8, further comprising peeling off the cut portion of saidtissue layer.
 12. The method of claim 7, 9, 6, or 8, furthercomprising:rotating said blade by manual manipulation of the movementcontrol element to direct the orientation of said blade with respect tosaid knife; manually orienting said knife while simultaneously rotatingsaid blade to form a non-linear incision in said tissue layer; andmanually removing said cutting edge from cutting contact with saidtissue layer.
 13. The surgical knife of claim 1, whereinsaid secondhousing portion is disposed at an angle with respect to said firsthousing portion.
 14. The surgical knife of claim 13, wherein said anglebetween said first and second housing portions of said tubular body isbetween 80° and 110°.
 15. The surgical knife of claim 13 wherein saidturning unit comprises a micro gear.
 16. The surgical knife of claim 1,wherein said turning unit comprises a linear rotatable element disposedthrough the first and second housing portions of said main body.
 17. Thesurgical knife of claim 1, whereinthe turning unit comprises first andsecond transversely oriented bevel gears.
 18. The surgical knife ofclaim 1, wherein said second housing portion of said main body and saidturning unit comprise flexible portions.
 19. The surgical knife of claim1, wherein the cutting edge of the blade is arcuate.
 20. The surgicalknife of claim 1, wherein the blade is triangular.
 21. The surgicalknife of claim 1, wherein the movement control element comprises a knobmounted to an end of the turning unit for rotation about the primaryaxis.
 22. The surgical knife of claim 1, wherein the movement controlelement comprises a slide control knob.
 23. The surgical knife of claim1, wherein the movement control element comprises a knob mounted to theturning unit for rotation about an axis perpendicular to the primaryaxis.
 24. A surgical knife comprising:a tubular main body having aprimary axis extending from one end to another end of the tubular mainbody, a blade mount disposed to extend from the tubular main body nearthe one end, and a movement control element disposed to extend from thetubular main body and spaced from the blade mount a distance along theprimary axis toward the other end; a turning unit disposed within thetubular main body, the turning unit comprising a band aligned along theprimary axis within the main body and extending from the movementcontrol element to the blade mount and cooperative with the blade mountand the movement control element; and a blade having a cutting edge, theblade being mounted to the blade mount to extend at an angle to saidprimary axis, whereby the orientation of the blade with respect to themain body may be altered by movement of the movement control element.25. The surgical knife of claim 24, wherein the movement control elementcomprises a knob.
 26. The surgical knife of claim 25 wherein said bladeis detachably mounted on said blade mount.
 27. The surgical knife ofclaim 24, said band being wrapped around said blade mount near the oneend of said main body and wrapped around said knob near the other end ofsaid main body.
 28. The surgical knife of claim 27 wherein said band isselected from a group consisting of a coiled spring, silicone rubber,polytetrafluoroethylene, and polyurethane elastomer.
 29. A surgicalknife comprising:a tubular main body having a primary axis extendingfrom one end to another end of the tubular main body, a blade mountdisposed to extend from the tubular main body near the one end, and aslide control element disposed to extend from the tubular main body andspaced from the blade mount a distance along the primary axis toward theother end; a turning unit disposed within the tubular main body, theturning unit comprising rack and pinion elements cooperative with theblade mount and the slide control element; and a blade having a cuttingedge, the blade being mounted to the blade mount to extend at an angleto the primary axis, whereby the orientation of the blade with respectto the main body may be altered by movement of the slide controlelement.
 30. A remotely operable surgical knife comprising:a tubularmain body having a primary axis, said tubular main body comprising anelongated first portion aligned along said primary axis and a shortersecond portion extending from said first portion to form an angle withrespect to said first portion; a turning unit disposed within said mainbody, said turning unit comprising:a turning mechanism comprising amicro gear in the main body at the juncture of the first and secondportions, the micro gear comprising rack and pinion elements; a movableelement extending through the first portion of said main body andattached to the turning mechanism, the movable element having an endattached to a slide control knob, wherein movement of the slide controlknob in the direction of the micro gear causes the rotation of theblade; and a blade mounting portion in the second portion of the mainbody and attached to said turning mechanism; and a blade mounted on saidblade mounting portion of said turning unit, wherein the orientation ofa cutting edge of said blade with respect to said main body isdetermined by movement of said movable element.
 31. Remotely operablesurgical scissors comprising:a tubular main body comprising an elongatedfirst portion having one end and a shorter second portion having oneend, said second portion extending from said first portion distal to theone end of said first portion to form an angle greater that 45° to saidfirst portion; a turning unit extending through said main body, saidturning unit comprisinga turning mechanism in the main body at thejunction of the first and second portions, said turning mechanismcomprising a micro gear, a movable element through the first portion ofsaid main body and having one end attached to the turning mechanism, anda scissors mounting portion in the second portion of the main body;scissors mounted on said scissors mounting portion, wherein movement ofa second end of said moveable element causes rotation of said scissorsabout an axis generally aligned with the second portion of the mainbody; and a scissors controlling element connected to said scissors andextending through said main body from said one end of said secondportion to said one end of said first portion for controlling operationof said scissors.
 32. A method of performing eye surgery within aninterocular incision in the sclera and conjunctiva, between the corneaand an anterior capsular membrane, and through an iris, for incising aportion of said anterior capsular membrane, said methodcomprising:manually inserting an ophthalmic knife through saidinterocular incision, said ophthalmic knife comprising:a tubular mainbody having a primary axis, a first housing portion aligned along theprimary axis, and a second housing portion disposed adjacent to saidfirst housing portion; a blade mount attached to the second housingportion and journaled for rotation about a secondary axis disposed at anangle with respect to the primary axis; and a blade having a cuttingedge, the blade mounted to the blade mount to extend from the secondhousing portion of the tubular body along the secondary axis; a turningunit disposed within the second housing portion in cooperation with theblade mount to rotate the blade mount; and a movement control elementdisposed to extend from the first housing portion of the main body andoperatively connected to the turning unit to cause movement of theturning unit, wherein movement of the control element causes rotation ofthe blade about the secondary axis; manually rotating said blade bymanual manipulation of said movement control element to direct theorientation of said blade with respect to said ophthalmic knife;manually orienting said ophthalmic knife while simultaneously rotatingsaid blade to form a continuous, non-linear incision in said anteriorcapsular membrane; and manually removing said ophthalmic knife from saidincision.